Such converter modules are intended in particular for use on-board satellites in order to power a telecommunications bus. The power supply system is controlled from a main control system CMEA which delivers the signals required for operating the various modules.
On-board systems generally have three operating ranges, and sometimes only two operating ranges:
I) a regulation range or daytime mode: excess power supplied by the solar cells is diverted or "shunted" sequentially, e.g. using the so-called "S3R" technique; PA1 II) the battery charging range (BCR): excess power delivered by the solar cells is used to charge the or each battery, and the charging current is controlled by a signal supplied by the amplifier MEA; and PA1 III) the battery discharge range (BDR) or "nighttime mode": current discharge from the batteries is controlled by a signal supplied by the amplifier MEA. PA1 a) the controlled switch can be in its closed position only if the shunt switch is in its active position; PA1 b) the controlled switch and the shunt switch are controlled in phase opposition; PA1 c) the control circuit controls the shunt switch as a function of the result of comparing the output voltage from the module and the current flowing through the first self-inductive element with respective thresholds; PA1 d) the control circuit has a logic element that deactivates closure of the shunt switch when the control circuit is in a state of drawing current from or discharging the second source; and PA1 e) the controlled switch is activated on or off in response to comparing a sawtooth signal with the output voltage of the module.
When two-range operation is used, then range II (battery charging) is omitted.
A more detailed description of a three-range system can be found in particular in the publication by P.R.K. CHETTY, entitled "Improved power conditioning unit for regulated bus spacecraft power system", published in the ESA Proceedings SP126 of the "3rd ESTEC Spacecraft Power Seminar", Sep. 21-23, 1977--NOORDWIJK (pp. 101-110).
In that technology, each of the operating ranges is provided by a specific module. For example, the prior art system shown in FIG. 1 implements 32 shunt modules numbered 1 to 32 and powered by the signals S3R, 12 battery discharge regulator modules numbered 1' to 12' and powered by signals BDR, and four battery charging regulator modules numbered 1" to 4" and powered by the signal BCR.
The modules 1 to 32 and 1' to 12' power the line BUS having capacitance C via forward-connected diodes as shown.
The modules 1 to 32 and 1" to 4" are powered by the current SA generated by the solar cells, while the modules 1' to 12' and 1" to 4" are powered by the voltage delivered by the storage battery(ies) BAT.
As shown in FIG. 1, the prior art system is complicated both from the point of view of the number of modules and from the point of view of the interconnections required.
Proposals have already been made to implement both-way modules that perform both battery charging II and discharging III. The resulting saving in terms of complexity is relatively marginal, since integrating the charging function makes it possible to omit only a small number of modules (see FIG. 1).
Proposals have also been made for a circuit that regulates by means of a switched "buck" regulator. Reference on this topic can be made to the article by G. SHIVANNA entitled "A new universal spacecraft power conditioner", published in "ESA Proceedings of 4th European Research Organization", September 1995, pp. 41 to 45.